3. (a) Explain how excess groundwater recharge can be dangerous for our environment. [6 Marks] (b) A well with 30 cm diameter and depth of 50 m below the static water table is available in unconfined aquifer. Two test wells exist in 40m and 200 m distance from the main well. After 36 hr of pumping with a discharge 4.0 m/minute the drawdown in the former test well is 2.7 m and in the Later one is 1.2m. i) Illustrate the aquifer system using a sketch. ii) Determine radius of zero draw-down. iii) Find coefficient of permeability. iv) Compute draw-down in the pumped well. v) What is the transmissibility of the aquifer? You may find following expression useful: ak H-h _h Q Ln R [19 Marks] [25 MARKS]